Abstract
BACKGROUND: Antiarrhythmic therapy for recurrent ventricular arrhythmias in patients who have undergone catheter ablation, and in whom amiodarone and/or beta-blockers were ineffective or contraindicated, is a controversial issue. OBJECTIVE: The present study sought to evaluate the efficacy and tolerability of oral procainamide in patients with recurrent ventricular arrhythmias when the standard therapy strategy had failed. METHODS: All patients treated with procainamide for recurrent ventricular tachycardia (VT) or ventricular fibrillation (VF) in our institution between January 2010 and May 2019 were enrolled. The primary endpoint was the total number of implantable cardioverter-defibrillator (ICD) interventions after the beginning of procainamide therapy. Secondary endpoints were the total number of VTs and VFs recorded on the ICDs' controls and discontinuation of therapy. The events occurring during procainamide treatment were compared with a matched-duration period before the initiation of therapy with procainamide. Patients therefore served as self-controls. RESULTS: A total of 34 consecutive patients (32 male, 94.1%; mean age 74.4 ± 9.7 years) were included in the retrospective analysis. The mean time of procainamide treatment was 12.9 ± 13.7 months (median 9 [2-20] months). The mean dose of procainamide was 1207 ± 487 mg/day. Procainamide therapy significantly decreased ICD interventions (median 5 [0-22.5] vs 15.5 [3-32.25], P < .05). Procainamide also decreased the total number of VT/VF episodes (median 5.5 [0.75-30] vs 19 [7.5-30], P < .05). Only 3 patients (8.8%) presented severe side effects (dyspnea or hypotension), requiring discontinuation of therapy. CONCLUSION: Oral procainamide was associated with a significant decrease in ICD therapies and ventricular arrhythmias, showing an acceptable profile of tolerability.